Supermarkets are steadily installing more and more self-service check-outs (and even boasting about it), at the same time getting rid of workers, or at least not replacing those who leave. In some branches an assistant is given the job of collaring shoppers in the queue for the check-out and persuading them to use the self-service facility.
Shoppers should politely decline, insist on being served, and explain that they are in fact defending the same assistants’ jobs.